Indoor Light Positioning Technology Based On Specular Reflection

Visible light positioning technology has received extensive attention from scholars because of its advantages such as simple deployment,environmental protection,no electromagnetic interference,and no spectrum certification.With the advance of the research,indoor visible light positioning models become more abundant,and the corresponding algorithms are also improved.However,the existing research of channel models only focus on diffuse reflection and ignore the importance of specular reflection.Therefore,based on the existing indoor communication model,this thesis proposes a communication model involving specular reflection,and designs a positioning scheme incorporating specular reflection power.First of all,the necessity and feasibility of introducing specular reflection into indoor positioning is described,combined with the actual use of mirror and the physical characteristics of specular reflection.Therefore,an indoor visible light positioning system with mirror is designed,and a simplified calculation of specular reflection power by using the virtual lamp is proposed.Secondly,a positioning algorithm that integrates specular power is proposed based on the three-point positioning algorithm of the received signal strength(RSS).With this algorithm,the specular reflection power is integrated into the effective positioning power,based on the multi-path transmission resistance and high reflectivity of the specular reflection,which can effectively improve the positioning accuracy.Results show that the proposed scheme significantly improves the positioning accuracy and overcomes the problem of positioning failure when the direct power is blocked by obstacles,compared with the traditional diffuse reflection model.Finally,a two-point location algorithm based on the virtual lamp is proposed.The virtual lamp is used as an independent light source for positioning work,separated from the real lamp by the light pulse signal arrival time difference between the specular reflection and the direct.Because virtual lamps are always accompanied by real lights,it is theoretically possible to achieve three-point positioning with only two physical light sources.Results show that the two-point positioning scheme is feasible,but it has some limitations,because only the area near the mirror wall can be located,with the average positioning error of 14.9cm.Furthermore,aiming at the scene where the obstacle blocks the direct link in the two-point positioning,two positioning methods are proposed,direct method and indirect method.Results shows that the indirect method has higher positioning accuracy,but the misjudgment of the light source introduces an additional positioning error of 3.3cm to 4.8cm,compared with the two-point positioning scene without obstruction.